The primary aim of this project is to develop a novel x-ray imaging system for imaging small animals in-vivo. This system will provide two resolution modes at 20um and 2um utilizing a novel concept for phase imaging which results in reduced exposure time and radiation dose. In comparison with absorption contrast used in current commercial imaging systems, the phase contrast will be highly sensitive to imaging soft tissues for studying cancer, angiogensis and phenotyping. In addition to its 2D phase imaging capability it will be capable of performing 3D quantitative phase tomography on an anesthetized animal. The 20um resolution mode has a field of view of 20mm while the 2um mode has a field of view of 2mm. The two resolution modes offer flexibility that is not currently available.